This summary of a Cochrane review presents what we know from research about the effects of cold therapy as a therapeutic intervention right after total knee replacement surgery for patients with osteoarthritis.
The review shows that in people who have had a total knee replacement:
- Cryotherapy may slightly reduce the amount of blood loss and pain
- Cryotherapy was generally safe and not associated with any serious adverse events
- Cryotherapy may improve the range of movement at the knee in the first one to two weeks after surgery
- No studies were found that looked at the effects of cryotherapy on a person's activities related to knee function (or quality of life, or general activity level)
What is total knee replacement and what is cold therapy?
Osteoarthritis is a disease of the joints, such as your knee. Osteoarthritis of the knee can make the knee joint painful and restrict function. Knee replacement surgery is a treatment that can help in this condition in the long term, but the effects of surgery during the recovery period (i.e. up to the first six months) are debilitating. Cold therapy (or cryotherapy) involves the application of very low temperatures to the skin surrounding an injury or surgical site. This can be by means of bags of ice or specialised devices that deliver cooled water to the area.
This review shows that there is evidence that cryotherapy may reduce pain and increase the range of movement in the first few days after a total knee replacement, but the use of cryotherapy does not reduce the need for blood transfusion. Use of cryotherapy is safe and did not result in an increase in serious complications.
Best estimate of what happens to people who have a total knee replacement and receive cryotherapy:
- People who received cryotherapy had on average 225ml less blood loss than people who did not have cryotherapy
- People who received cryotherapy reported less pain day 2 postoperatively, on average 1.3 points less on a scale of 0 to 10, but pain levels at day 1 and day 3 showed no difference.
Adverse events (unwanted effect including discomfort, local skin reactions, skin infections, cold-related injuries and blood clots)
- 34 out of 1000 people who received cryotherapy experienced one or more unwanted effects
- 34 out of 1000 people who did not receive cryotherapy also experienced one or more unwanted effects
Range of motion
- People who received cryotherapy were able to bend their knee 11 degrees more at the time of discharge from hospital
Transfusion rate (the requirement for a blood transfusion after the surgery)
- This was not reduced in patients who had cryotherapy
- There was no evidence found about the effects of cryotherapy on knee function
Potential benefits of cryotherapy on blood loss, postoperative pain, and range of motion may be too small to justify its use, and the quality of the evidence was very low or low for all main outcomes. This needs to be balanced against potential inconveniences and expenses of using cryotherapy. Well designed randomised trials are required to improve the quality of the evidence.
Total knee replacement (TKR) is a common intervention for patients with end-stage osteoarthritis of the knee. Post-surgical management may include cryotherapy. However, the effectiveness of cryotherapy is unclear.
To evaluate the acute (within 48 hours) application of cryotherapy following TKR on pain, blood loss and function.
We searched the Cochrane Database of Systematic Reviews, CENTRAL, DARE, HTA Database, MEDLINE, EMBASE, CINAHL, PEDro and Web of Science on 15th March 2012.
Randomised controlled trials or controlled clinical trials in which the experimental group received any form of cryotherapy, and was compared to any control group following TKR indicated for osteoarthritis.
Two reviewers independently selected trials for inclusion. Disagreements were discussed and resolved involving a third reviewer if required. Data were then extracted and the risk of bias of trials assessed. Main outcomes were blood loss, visual analogue score (VAS) pain, adverse events, knee range of motion, transfusion rate and knee function. Secondary outcomes were analgesia use, knee swelling, length of hospital stay, quality of life and activity level. Effects of interventions were estimated as mean differences (MD), standardised mean differences (SMD) or given as risk ratios (RR), with 95% confidence intervals (CI). Meta-analyses were performed using the inverse variance method and pooled using random effects.
Eleven randomised trials and one controlled clinical trial involving 809 participants met the inclusion criteria. There is very low quality evidence from 10 trials (666 participants) that cryotherapy has a small benefit on blood loss (SMD -0.46, 95% CI, -0.84 to -0.08), equivalent to 225mL less blood loss in cryotherapy group (95% CI, 39 to 410mL). This benefit may not be clinically significant. There was very low quality evidence from four trials (322 participants) that cryotherapy improved visual analogue score pain at 48 hours (MD = -1.32 points on a 10 point scale, 95% CI, -2.37 to -0.27), but not at 24 or 72 hours. This benefit may not be clinically significant. There was no difference between groups in adverse events (RR = 0.98, 95% CI, 0.28 to 3.47). There is low quality evidence from two trials (107 participants) for improved range of motion at discharge (MD 11.39 degrees of additional flexion, 95% CI 4.13 to 18.66), but this benefit may not be clinically significant. There was no difference between groups in transfusion rate (RR 2.13, 95% CI 0.04 to 109.63), and knee function was not measured in any trial. No significant benefit were found for analgesia use, swelling or length of stay. Outcomes measuring quality of life or activity level were not reported.